1. Field of the Invention
The present invention relates to a digital video recorder having an apparatus for receiving an automatic switched image by recognizing a source and a method thereof, which is capable of automatically determining whether an image channel is a SD signal channel or a HD-SDI signal channel and switching between these channels.
2. Description of the Related Art
When a conventional SD class CCTV is to be switched to a HD class monitoring system, an IP-based NVR is a target for switching. However, an IP-based system requires removal of existing CCTV infrastructures and construction of a new IP-based infrastructure, which acts as a barrier against introduction.
In this regard, in recent years, a DH-SDI (High Definition-Serial Digital Interface) technology to utilize the existing CCTV infrastructure to enable HD image monitoring is in the spot light.
As one of digital video transmission standards specified by SMPTE (Society of Motion Picture and Television Engineers), HD-SDI is being mainly used for HD cameras and broadcasting equipment for HD digital broadcasting.
In particular, a HD-SDI format beneficial for implementation of high definition image with the minimum of 720p (1280×720) begins to create a boom in company with the demand of CCTV market to seek high quality images.
A HD CCTV of the HD-SDI format can reuse the existing CCTV infrastructure and the HD CCTV and HD DVR provide the same user interface (UI) as architecture of existing CCTV and DVR.
In addition, a HD CCTV camera has many merits in that it can transmit a digital video as well as 720p and 1080p image formats corresponding to a resolution about six times as high as that of an NTSC/PAL system.
However, the HD CCTV of the current HD-SDI has a demerit of limitation on an image transmission distance and expensive parts.
For example, to facilitate reuse of the HD CCTV infrastructure, the image transmission distance has to be more than 300 mm, like existing CCTVs but does not reach a half thereof with the current HD-SDI technique.
In addition, HD-SDI transmission/reception chip sets serving as core parts of HD-SDI techniques are more expensive than IP type high-definition cameras.
In this manner, since the image transmission distance is much reduced when the HD-SDI technique is applied to lines for existing SD class image transmission, reutilization of the existing lines is practically infeasible and distance limitation frequently occurs in on construction of new lines.
Accordingly, in recent years, for the purpose of facilitating reutilization of existing lines, there has been proposed a DVR in which some channels support HD-SDI and some channels support SD while using HD class image monitoring only for a region requiring high-definition monitoring, whereas using SD class image monitoring for a region requiring no high-definition monitoring.
FIG. 1 is a block diagram of a DVR having the existing SD signal channel 1 and HD-SDI signal channel 2.
Referring to FIG. 1, the existing SD signal channel 1 provides SD class image which is decoded by a SD analog decoder 5. An image output from an image processing unit 7 is reproduced on a monitor 8 or stored in a storage 9.
The HD-SDI signal channel 2 in a region requiring high-definition monitoring provides a HD-SDI class image which is decoded by a receiver 6. An image output from the image processing unit 7 is reproduced on the monitor 8 or stored in the storage 9.
However, due to physical separation of the SD signal channel 1 and the HD-SDI signal channel 2, this configuration has a difficulty in installation of these channels 1 and 2. In addition, since these channels 1 and 2 use the same BNC interface, an installation error occurs frequently when general users install or changes these channels 1 and 2.
In addition, the DVR having the existing SD signal channel 1 and HD-SDI signal channel 2 have a low possibility of reutilization of existing lines. Further, since these channels 1 and 2 are not easy to be changed, the DVR is too inconvenient to use it due to low flexibility of channel setting and installation.